Polymers of alkyl alpha-acyloxy-acrylates



Patented July 10, 1951 2,559,635 FICE POLYMERS OF ALKYL a-ACYLOXY- ACRYLATES William 0. Kenyon, Thomas '1. M. Laakso, and Cornelius C. Uni-uh, Rochester, N. Y., asslgnors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application March 1, 1950,

Serial No. 147,161

18 Claims. (Cl. 260-855) This application relates to new interpolymers of alkyl a-acyloxyacrylates, and to a process for obtaining them.

This application is a continuation-in-part of our application Serial No. 776,154, filed September 25, 1947, now U. S. Pat. No. 2,499,343, dated March 7, 1950.

Spence & Degering U. 5. Patent 2,407,302, dated September 10, 1946, shows that esters of a-acyl oxyacrylic acids can be prepared by reacting a ketene with an ester of pyruvic acid. however, a reaction mixture which is diflicult to separate into its component parts usually results. The products so prepared are obtained in low yields and are homopolymerized with extreme difliculty. In our application Serial No. 776,154 (U. S. Patent 2,499,393), we have shown a new process for preparing these esters, which are obtained in high yields and can be homopolymerized without difficulty. We have also shown in that application that certain interpolymers can be obtained from these esters of a-acyloxyacrylic acids.

We have now found that some of these interpolymers are characterized by unique solubility properties in organic solvents, and are readily adaptable for certain purposes such as molding. For example, while both polystyrene and polyethyl a-acetoxyacrylate are insoluble in acetone, we have found that certain interpolymers prepared from the respective monomers of these homopolymers can be readily dissolved in acetone.

We have observed further that the homopolymers of alkyl a-acyloxyacrylates are not readily adaptable to molding, since their softening temperatures are generally above their decomposition temperatures. The use of plasticizers to cure this difiiculty has not proved to be especially efficacious, since the plasticizers in many instances undergo decomposition themselves, causing discoloration. The interpolymerization properties of these alkyl a-acylo:-:yaer5-'lates are also of some interest, in some instances interpolymers being readily formed, while in others it being doubtful that interpolymers actually form. In some instances, there seems to be evidence that the alkyl a-acyloxyacrylates slow the rate of polymerization of the other monomer.

However, we have found that within certain ranges of proportions styrene, methyl, a-methacrylate, and acrylonitrile form valuable interpolymers with the alkyl a-aeyloxyacrylates of our prior application.

It is, therefore, an object of our invention to provide new interpolymers of alkyl aacyloxyacrylates.

A further object is to provide new methods for preparing these interpolymers.

Still another object is to provide shaped articles prepared from our new interpolymers,

Other objects will become apparent from a. consideration of the following description and examples.

According to our invention we prepare our new interpolymers by heating in the presence of a peroxide polymerization catalyst a mixture selected from the group consisting of a mixture containing from 10 to 60 per cent by weight of the alkyl a-acyloxyacrylate and from to 40 per cent by weight of styrene, a mixture containing from 10 to 90 per cent by weight of the alkyl a-acyloxyacrylate and from 90 to 10 per cent by weight of methyl a-methacrylate, and a mixture containing from 10 to 40 per cent by weight of the alkyl a-acyloxyacrylate and from 90 to 60 per cent by weight of acrylonitrile.

The alkyl a-acyloxyacrylates which can be used in our invention can be represented by the following general formula:

wherein R represents an alkyl group, such as methyl, ethyl, n-propyl, and isopropyl (i. e. an alkyl group of the formula CnH2n+1 wherein n represents a positive integer of from 1 t0 3) and R1 represents an alkyl group, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, etc. (i. e. an alkyl group of the formula CnH2n+1) wherein n represents a positive integer from 1 to 4. Typical esters include methyl, ethyl, npropyl, isopropyl, n-butyl, isobutyl, etc. a-acetoxyacrylates; methyl, ethyl, n-propyl, isopropyl, nbutyl, isobutyl, etc. a-n-propionoxyacrylates; and methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, etc. a-n-butyroxyacrylates and a-lSO- butyroxyacrylates. As mentioned above, our application Serial No. 776,154 (U. S. Patent 2,499,- 393) discloses a method for making these alkyl a-acyloxyacrylates. Still another method is described in the copending application Serial No. 775,144, filed September 19, 1947, now U. S. Patent 2,499,392, dated March 7, 1950, of William O. Kenyon and Cornelius C. Unruh. Still another method for preparing these esters is set forth in the copending application Serial No. 22,504, filed April 21, 1948, now U. S. Patent 2,514,672, dated July 11, 1950, of William O. Kenyon and Delbert D. Reynolds.

Polymerization catalysts which can be used in our invention include the organic peroxides e. g. benzoyl peroxide, acetyl peroxide, acetyl benzoyl peroxide, lauroyl peroxide, oleoyl peroxide, acetone peroxide, urea peroxide, etc.), hydrogen peroxide,alkali metal perborates (e. g. sodium and potassium perborates), alkali metal persulproximately 15:1 in the copolymer. Example 2.-Interpoly'mer of styrene and ethyl fates (e. g. sodium and potassium-persulfates), ammonium persulfate, ammonium perborate, etc.

Temperatures varying from about room temperature (20-25 C.) to about 65 C. have been found to be especially eflicacious in practicing our invention, although higher temperatures can be used. if desired.

The polymerization can be carried out by the head or emulsion method in which water, or some other medium in which the monomers are insoluble, is employed as a dispersing medium, with or without emulsifying agents. The polymerization can also be performed by use of a solvent which dissolves the monomers, but not the polymer, which precipitates from the solution a it forms. Alternatively, the diluent or solvent, such as benzene, toluene, xylene, 1,4-dioxane, acetonitrile. acetone, N,N-dimethylformamide, succinonitrile, glycolonltrile (formaldehyde cyanohydrln), etc. can be a solvent for the polymer. The polymerization can also be carried out by the mass method.

The following examples illustrate further the manner whereby we practice our invention.

Example 1.Interpolymer of methyl a-methacry'late and ethyl a-acetoxyacrylate 15.8 gms. of ethyl a-acetoxyacrylate, 10.0 gms. of methyl a-methacrylate, and 0.13 gm. of henzoyl peroxide were placed in a sealed glass tube under an atmosphere of nitrogen and the tube placed in a constant temperature water bath maintained at 50 C. After three days a clear, hard resin was formed, which was dissolved in acetone. This solution was then poured into an excess of methanol, the resulting precipitate redissolved in acetone, and the resulting solution poured into hot water. After drying the reprecipitated product at 50 C., a yield of 24 gms. of copolymer was obtained. The acetyl content of the copolymer was found by distillation to be 14.7%, representing a molar ratio of methyl a-methacrylate to ethyl a-acetoxyacrylate of apa-acetozcyaorylate 15.8gms. of ethyl a-acetoxyacrylate, 10.4 gms.

I styrene to the ethyl a-acetoxyacrylate of approximately 1.121 in the copolymer.

Example 3.Interp0lymer of methyl a-methacrylate and ethyl a-n-butyroxacrylate 9.3 gms. of ethyl a-butyroxyacrylate, 5.0 gms. of methyl a-methacrylate, and 0.072 gm. of benzoyl peroxide were sealed together in a glass ampoule under an atmosphere of nitgrogen. The ampoule was then placed in a constant temperature bath maintained at C. After 3 days a clear, colorless, hard resin was formed.

Example 4.'-Interp0lymer of styrene and ethyl a-n-but'yroryacrylate 9.3 gms. of ethyl a-butyroxyacrylate, 5.2 gms. of styrene, and 0.072 gm. of benzoyl peroxide were sealed together in a glass tube under an atmosphereoi' nitgrogen. The tube was placed in a constant temperature bath maintained at 50 C. After 7 days a clear, colorless, and hard resin was formed.

Example 5.-Interpolymer of styrene and isobutyl a-acetoaryacrylate 9.3 gms. of isobutyl a-acetoxyacrylate, 5.2 gms. of styrene, and 0.072 gm. of benzoyl peroxide were placed in a sealed glass tube under an atmosphere of nitrogen. The tube was placed in a constant temperature bath maintained at 50 C. After 7 days a clear, colorless, and hard resin had formed.

Example 6.Interp0lymer of methyl a-methacrylate and isobutyl a-acetoxyacrylate 9.3 gms. of isobutyl a-acetoxyacrylate, 5.0 gms. of methyl a-methacrylate, and 0.072 gm. of henzoyl peroxide were sealed together in a glass ampoule under an atmosphere of nitrogen and placed in a 50 C. bath maintained at constant temperature. After 3 days a clear, colorless, and hard resin was formed.

In a manner similar to that shown in Example 2 above, the amounts of styrene, ethyl a-acetoxyacrylate, and benzoyl peroxide shown in the table below were heated together at the temperature indicated for 90 hours in each instance. The appearance of the product and the yield thereof are also shown. The products were separated from the reaction mixture as shown in Example 2.

of styrene and 0.13 gm. of benzoyl peroxide were placed in a sealed ampoule under an atmosphere of nitrogen. The ampoule was placed in a constant temperature bath maintained at 50 C., and after 6 days a hard, clear resin was formed. This was dissolved in 1,4-dioxane, the solution poured into an excess of stirred methanol. Th precipitate was again dissolved in 1,4-dioxane, and the solution poured into an excess of hot water. After the resulting precipitate was dried at 50 C., a yield of 24 gms. of copolymer was obtained. The ethoxyl (C2H5O) content of the copolymer was found to be 16.6%, indicating a molar ratio of ing the precipitates with methanol for 16 hours,

they were dried at 55 C.

The reaction mixture obtained in Example 14 was diluted with acetone, and then poured into an excess of methanol. The precipitate was dissolved in acetone and poured into an excess of distilled water. The white fibrous precipitate was dried at 55 C.

6 ture was placed in a closed glass vessel and tumbled in a 50 C. water bath for 3 days. On opening the vessel, the small transparent beads were separated and dissolved in 1,4-dioxane.

Methyl a-methacrylate, ethyl a-acetoxyacrylate, and benzoyl peroxide were heated together at similar to that shown in Example 1. The prod- 55 C. on a water bath for 48 hours in a manner 2') The polymer was precipitated by pouring into excess methanol with vigorous stirring. The precipitate was dissolved in acetone and recovered by pouring the solution into an excess of distilled ucts were recovered as described in Example 1 water. The white, fibrous precipitate was dried and the results are shown in Table III below. at 50 C.

TABLE III Wt.Methl Wt. Ethyl Wt. Ben- Ex. r-Methrz-Acetoxyzoyl i 24 Yield acrylate acrylate Peroxide Grams Grams Grams Grams 1 9 0.05 Clear, hard, colorless.-. 9. 2 s 0.05 do 9.5 4 s 9.5 6 4 9.5 s 2 9.5 9 1 9.5

Example 21 .S0luti0n interpolymerization of styrene and ethyl a-acetomyacrylate 7.9 gms. of ethyl a-acetoxyacrylate and 5.2 gms. of styrene were dissolved in cc. of dry 1,4-dioxane in a glass tube and 9.0% gm. of benzoyl peroxide added. The tube was sealed with the contents under a nitrogen atmosphere, and then heated at 55 C. for 5 days. The clear, colorless, viscous mass was diluted with acetone and poured into excess methanol. It was again dissolved in acetone and poured into distilled water, whereupon a white, fibrous product prec1pitated.

Example 22.Interpolymer of styrene and nbutyl a-acetoxyacrylate 18.6 gms. of n-butyl a-acetoxyacrylate, 10.4 gms. of styrene, and 0.15 gm. of benzoyl peroxide were sealed together in a glass tube under an atmosphere of nitrogen. After heating the tube at 55 C. in a water bath for 72 hours, the contents of the tube had set to a hard, clear, colorless mass, which was dissolved in acetone. This solution was poured into rapidly-stirred excess methanol, and the resulting precipitate was redissolved in acetone and then poured into distilled Water. After the white, fibrous precipitate was dried in an oven at 55 C., 28.5 gms. of product were obtained.

Example 23.--Bead interpolymerieation of styrene and ethyl a-acetoxyacrylate A solution of 7.9 gms. of ethyl a-acetoxyacrylate, 5.2 gms. of styrene, and 0.065 gm. of henzoyl peroxide was mixed with cc. of a one per cent solution of gum arabic in water. The mix- Example 24.Interpolymer of acrylonitrile and n-butyl a-acetozcyacrylate 2.5 gms. of n-butyl -a-acetoxyacrylate, 10.0 gms. of acrylonitrile, 18.7 gms. of acetonitrile, and 0.031 gm. of benzoyl peroxide were sealed in a glass tube under nitrogen, and heated at 55 C. for 6 days. The slightly hazy, light brown, gelatinous mass was dissolved in N,N-dimethylformamide, and the solution filtered. The light tan solution was poured into an excess of wellstirred methanol, and the resulting precipitate was leached for several hours with fresh methanol (2 changes) and then dried at 55 C. were obtained 8 gms. of product containing 19.1 per cent nitrogen, corresponding to 72.3 per cent acrylonitrile in the interpolymer.

Example 25.--Interpolymer of methyl a-methacrylate and n-butyl e-acetoxyacrylate 18.6 gms. of n-butyl a-acctoxyacrylate, 10.0 gms. of methyl cl-methacrylate and 0.15 gm. of benzoyl peroxide were sealed in a glass tube under nitrogen and the tube ilaced in a water bath at 55 C. After 2 1 hours a hard, clear, and colorless mass was obtained which was dissolved in acetone. The solution was poured into excess methanol and the resulting precipitate was dissolved in acetone. This solution was poured into distilled Water and the white, fibrous precipitate was dried in an oven at 55 C.- It weighed 255 gms.

Several of the polymers obtained in the above examples were molded in a standard molding press, using steel molds, under a pressure of about 8 tons for 2 minutes. The molding temperatures There accaesc A mula CnHZrH-l wherein n represents a positive integer of from 1 to 3 and R1 represents an alkyl and the appearance of the products after mold,- ing are shown in Table IV below.

60 40 20 10 60 10 20 40 90 8O 60 4O l 10 64 65 EAA 150 Clear, 51. yello EAA 140 Clear, colorless EAA 140 Do.

EAA 121) Do.

EAA 120 Do.

EAA 120 D0.

EAA 130 Dd BAA 100 Do.

BAA 100 Do.

BAA 120 Clear, amber.

EAA-ethyl urBCGtOXYBClYlfltQ. B AA-n-butyl a.-acetoxyacrylete. MMA =methyi wmethacrylate.

The interpolymers of our invention can also be spun into fibers, cast into sheets, extruded into tubes, etc. Interpolymers can also be prepared from the alkyl a-acyloxyacrylates used above and other vinyl monomers such as acrylic acid, vinyl chloride, vinyl acetate, methyl acrylate, a-acetoxyacrylonitrile, monochlorostyrene, etc. However, these interpolymers do not generally exhibit the unique properties of the interpolymers disclosed in the above examples, and analysis of their compositions indicates in certain instances that a true interpolymer is not formed, but a mixture containing a small amount of interpolymer and some homopolymers.

What we claim as our invention and desire secured by Letters Patent of the United States is:

1. A resinous interpolymer of an alkyl a-ECYI- oxyacrylate selected from those represented by the following general formula:

group of the formula CnH-mm wherein n represents a positive integer from 1 to 4, and from 90 to 40 per cent by weight of styrene '3. A resinous interpolymer containing from 10 to 90 per cent by weight of an alkyl a-flCYlOXY- acrylate selected from those represented by the following general formula:

wherein R represents an alkyl group of the for- O mula CnH2n+1 wherein n represents a positive in- CH c g OR teger from 1 to 3 and R1 represents an alkyl group F of the formul CnI-Izn+1 wherein n represents a positive integer from 1 to 4, selected from the group consisting of an interpolymer containing from 10 to per cent by weight of the said alkyl aacylcxyacrylate and from 90 to 40 per cent by weight of styrene, an interpolymer containing from 10 to 90 per cent by weight of the said alkyl c-acyloxyacrylate and from 90 to 10 per cent by weight of methyl a-methacrylate, and an interpolymer containing from 10 to 40 per cent by weight of the said alkyl a-acyloxyacrylate and from 90 to 60 per cent by weight of acrylonitrile.

2. A resinous interpolymer containing from 10 to 60 per cent by weight of an alkyl a-acyloxyacrylate selected from those represented by the following general formula:

wherein It represents an alkyl group of the forwherein R represents an alkyl group of 141v formula CnH2n+1 wherein n represents a positive integer of from 1 to 3 and R1 represents an alkyl group of the formula CnHnm-i wherein n represents a positive integer of from 1 to 4, and from to 60 per cent by weight of acrylonitrile.

5. A resinous interpolymer containing from 10 to 60 per cent by weight of ethyl a-acetoxyacrylate and from 90 to 40 per cent by weight of styrene.

6. A resinous interpolymer containing from 10 to 90 per cent by weight of ethyl a-acetoxyacrylate and from 90 to 10 per cent by weight of methyl a-methacrylate.

'7. A resinous interpolymer containing from 10 to 40 per cent by weight of ethyl c-acetoxyacrylate and from 90 to 60 per cent by weight of acrylonitrile.

8. A resinous interpolymer containing from 10 to 60 per cent by weight of n-butyl a.-acetoxyacrylate and from 90 to 40 per cent by weight of styrene.

9. A resinous interpolymer containing from to 90 per cent by weight of n-butyl a-acetoxy- 'acrylate and from 90 to 10 per cent by weight of wherein R. represents an alkyl group of the formula CnH2n+1 wherein n represents a positive integer from 1 to 3 and R1 represents an'alkyl group of the formula CnH2n+l wherein n represents a positive integer from 1 to 4, comprising heating in the presence of a peroxide polymerization catalyst a mixture selected from the group consisting of a mixture of from 10 to 60 per cent by weight of the said alkyl a-acyloxyacrylate and from 90 to 40 per cent by weight of styrene, a

mixture 01 from 10 to 90 per cent by weight of the said alkyl a-acyloxyacrylate and from 90 to 10 per cent by weight of methyl a-methacrylate, and a mixture of from 10 to 40 per cent by weight of the said alkyl-a-acyloxyacrylate and from 90 to 60 per cent by weight of acrylonitrile.

11. A process for preparing a resinous interpolymer comprising heating in the presence of a peroxide polymerization catalyst a mixture consisting of from 10 to 60 per cent by weight of an alkyl a-acyloxyacrylate selected from those represented by the following general formula:

wherein R represents an alkyl group of the formula CnI'IBnH wherein n represents a positive integer of from 1 to 3 and R1 represents an alkyl group of the formula CnH2n+l wherein n represents a positive integer from 1 to 4, and from 90 to 40 per cent by weight of styrene.

12. A process for preparing a resinous interpolymer comprising heating in the presence of a peroxide polymerization catalyst a mixture consisting of from 10 to 90 per cent by weight of an alkyl a-acyloxyacrylate selected from those represented by the following general formula:

10 V wherein R represents an alkyl group of the formula CnH2n+1 wherein n represents a positive integer of from 1 to 3 and R1 represents an alkyl group of the formula CnH2n+l wherein n represents a positive integer from 1 to 4, and from 90 to 10 per cent by weight of methyl a-methacrylate.

13. A process for preparing a resinous interpolymer comprising heating in the presence of a peroxide polymerization catalyst a mixture consisting of from 10 to per cent by weight of an alkyl a-acyloxyacrylate selected from those represented by the following general formula:

wherein R represents an alkyl group of the formula CnH2n+l wherein n represents a positive integer of from l to 3 and .-R1 represents an alkyl group of the formula CnH2n+l wherein n represents a positive integer from 1 to 4, and from 90 to 60 per cent by weight of acrylonitrile.

14. A process for preparing a resinous interpolymer comprising heating in the presence of a peroxide polymerization catalyst a mixture consisting of from 10 to 60 per cent by weight of ethyl a-acetoxyacrylate and 90 to 40 per cent by weight of styrene.

15. A process for preparing a resinous interpolymer comprising heating in the presence of a peroxide polymerization catalyst a mixture consisting of from 10 to 90 per cent by weight of ethyl a-acetoxyacrylate and. from 90 to 10 per I cent by weight of methyl a-methacrylate.

16. A process for preparing a resinous interpolymer comprising heating in the presence of a peroxide polymerization catalyst a mixture consisting of from 10 to 40 per cent by weight of ethyl a-acetoxyacrylate and from 90 to per cent by weight of acrylonitrile.

17. A process for preparing a resinous interpolymer comprising heating in the presence of a. peroxide polymerization catalyst a mixture consisting of from 10 to 60 per cent by weight of n-butyl a-acetoxyacrylate and from to 40 per cent by weight of styrene.

18. A process for preparing a resinous interpolymer comprising heating in the presence of a peroxide polymerization catalyst a mixture consisting of from 10 to 90 per cent by weight of n-butyl a-acetoxyacrylate and from 90 to 10 per 5 cent by weight of methyl a-methacrylate.

No references cited. 

1. A RESINOUS INTERPOLYMER OF AN ALKYL A-ACYLOXYACRYLATE SELECTED FROM THOSE REPRESENTED BY THE FOLLOWING GENERAL FORMULA: 